Apparatus for and method of combustion



Jan. 10, 1939. D. J. MOSSHART APPARATUS FOR AND METHOD OF COMBUSTION Filed April 19, 1935 e Sheets-Shet 1 i 4&5 12s INVENTOR 40W Jan. 10, 1939. D. JJMOSSHART APPARATUS FOR AND METHOD OF COMBUSTION Filed April 19, 1935 6 Sheets-Sheet 2 Jan. 10, 1939. J MOSSHART 2,143 834 APPARAT S FOR AND METHOD OF COMBUSTION Filed April 19, 1955 6 Sheets-Sheet 3 INVENTOR Jan. 10, 1939. b. J. 'MROSVSAHART 2,143,834

APPARATUS FOR AND METHOD OF COMBUSTION Filed April 19, 19 35 6 Sheets-Sheet 4 FIG. 6.

92 as so 4 ea 93 mo 12 Ham. 6,2 751 O INVENTOR Jan. 10, 1939. D. J. MOSSHART APPARATUS FOR AND METHOD OF COMBUSTION Filed April 19, 1935 6 Sheets-Sheet 5 IAJJENTOR F1GJ4.

Jan. 10, 1939. D. J. MOSSHART APPARATUS FOR AND METHOD OF COMBUSTION Filed April 19, 1935 6 Sheets-Sheet 6 hi fk INVENTOR Patented Jan. 10, 19 39 APPARATUS FOR AND 1mm F COMBUSTION Donald J Mosshart, Springfield, Pa., assignor of one-half to Harold F. Hildreth, Springfield,

Mass.

Application April 19, 1935, Serial No. 17,162'

14 Claims.

My invention relates to combustion apparatus and more particularly to Stoker-fired furnaces of the small capacity type, for example, of the type suitable for use in heating dwellings, small houses, apartments, etc., which are commonly referred to as domestic stoker furnaces.

My invention has for one of its objects to provide apparatus of this general type which is of improved construction and arrangement of parts and which is capable of burning efficiently any one of a wide variety of solid fuels with practically no care by an attendant.

A further object is to provide a stoker furnace of the domestic type which is capable of burning automatically and eificiently any coal of the caking, non-caking, or free-burning types and without. necessitating the care of an attendant to poke the fire or remove ash or clinker.

A further object is to provide a highly compact and conveniently arranged furnace unit whereby the fuel can be supplied thereto and ash removed therefrom with a minimum of labor.

A further object is to provide a furnace unit which is capable of being automatically regulated and which is adjustable throughout to meet widely varying load conditions.

A further object is to provide a stoker Furnace suitable for domestic use wherein the ash is automatically or mechanically ejected into a suitable portable receptacle without the aid of an attendant regardless of the type of solid fuel burned.

A further object is to provide a furnace unit which is so constructed that the fire can be brought from a banked condition to a full load condition in' a minimum of time, even though the furnace has been previously idle for a considerable length of time; thus providing a furnace which is admirably suited to meet 'widely varying conditions incident to heating buildings, homes, etc.

A further object is to provide a domestic stoker furnace wherein a fuel agitating member, for

example, an air-emitting grate, moves transversely of the mouth of an upwardly-inclined fuel feeding duct and toward and away from a duct following the resumption of furnace operation after a periodof shut-down.

A further object is to provide an improved.

is broken up by pressure exerted thereon by the incoming fuel.

A still further object is to provide an improved method of and apparatus for burning fuel in a furnace whereby ash provides a support for a fuel column moving across the furnace chamber and the column is broken up by the pressure exerted by the incoming fuel.

These and other objects are effected by my invention, as will be apparent, from; the following description and claims taken in connection with the accompanying drawings forming a part of this application, and in which:

Fig. 1 is a side elevational view showing my improved form of stoker fired furnace;

Fig. 2 is a vertical transverse sectional view taken on the line 2-2-of Fig. 1 showing certain parts of the operating mechanism in elevation for the purposes of clarity;

Fig. 3 is a longitudinal vertical sectional view taken on the line 3-3 of Fig. 2; V

Fig. 4 is a fragmentary view illustrating in vertical longitudinal section, one formof speed reduction drive mechanism for my improved stoker;

Fig. 5 is a plan view of the supporting guide plate for the' grate with the grate frame and grate bars in place thereon, the view being better understood by referring to the line 55 and directional arrows appearing on Fig. 3;

Fig. 6 is a View similar to Fig. 5, but showing the guide plate in plan with the grate frame and grate bars removed;

Fig. '7 is a longitudinal section-taken on the line l'| of Fig. 6;

Fig. 8 is a plan view of the grate frame without the grate bars;

Fig. 9 is a plan view of thegrate bars assembled without the frame;

Fig. 10 is a longitudinal vertical section of the grate frame, the view being taken on the .line |0l0 ofFig. 8;

Fig. 11 is a detail view, showing in side elevation one of the grate bars;

Fig. 12 is a detail view, showing in side elevation another of the grate bars Fig. 13 is a horizontal sectional view taken on the line |3|3 of Fig. 1 and illustrating more in detail my improved form of air control;

Fig. 14 is a fragmentary vertical section similar toFig. 3 showing the furnace in operation with the fuel bed therein, the view being somewhat diagrammatic in character;

Fig. 15 is a horizontal section taken on the line I5-l5 of Fig. 14;

' chosen to show my invention as applied to a heat- -ing furnace of a size suitable for domestic use.

The furnace structure is indicated in general by the reference numeral I0 and includes a combustion chamber defined by a front wall |2, a rear wall Hi and side'walls M and |5.

Solid fuel is supported during combustion by means of structure indicated generally by the reference numeral I6 and comprising a forwardly and rearwardly reciprocating air-emitting grate ll, slidably supported by a stationary guide plate IS, the latter being in turn suitably supported by the furnace structure H3. Brackets -|9 fixed to the side walls i4 and |5 form a part of the supporting means for the stationary guide plate it.

That part of the grate i? which is disposed adjacent the front wall I 2 and midway between the side walls l4 and 5 is constructed in the form of a U so as to provide an opening or channel through the grate. Solid fuel is fed upwardly through the opening or channel 20 from the upper open end of an inclined stationary duct 2|. In the sense that the space indicated by the reference character 20 is 'void of structure, it may be properly termed an opening; but, in the sense that this opening has substantial depth due to the height of its defining walls, it may also be properly referred to as a channel. The fuel is supplied to the lower end of the duct 2| from a suitable storage hopper 22. A rotating screw 23 within the duct 2| serves to feed the fuel from the hopper 22 longitudinally of the duct and upwardly through the opening 20 onto the grate H.

In so far as certain aspects of my invention are concerned, the screw 23 may be operated by any means suitable for imparting a rotary motion thereto, which means may be regulated to vary the amount of fuel fed to the combustion chamber. In the embodiment of my invention shown, I have chosen to show an electric motor 24, operatively connected through a speed reducing mechanism 25 to a shaft 26 having a bevel gear 2'! fixed to its outer end and meshing with a second bevel gear 28 fixed to the lower end of a shaft 29 on which the screw 23 is formed.

The mechanism 25 is shown in detail in Fig. 4 and is so constructed as to convert the constant rotary motion of the motor 24 into an intermittent rotary motion of the gear 21, which motion may be varied at will. The mechanism 25 comprises a shaft 30 connected to the motor 24 by a pulley 3| and belt 32, and connected to a shaft 33 through a worm 34 and worm wheel 35. The shaft 33 is provided with a crank 36 which drives the shaft 26 through a pawl and ratchet.

An arm 37 is loosely mounted at one end on the shaft 26 and is provided at its other and outer end with a swiveled member 38 which has an opening therethrough loosely receiving one end of a connecting rod 39, the other end of the latter being connected to the crank 36. A compression spring 40 encircles the rod 39 and abuts at one end thereof a collar 4| fixed to the rod 39 and at its other end a collar 42 formed on the swiveled member 38.

clockwise motion of the arm 31 will continue until the crank 36 has traveled 270 from the position shown, after which, forward or counter-clockwise motion will be imparted to the arm 31 through the spring 40, as previously explained.

A ratchet wheel 54 is fixed to the shaft 26 and is engaged by a pivoted pawl carried by the arm 37, and forward or counter-clockwise motion of the latter will cause the pawl to rotate the ratchet wheel 44 and shaft 26 an amount depending upon the point in the arc of forward movement of the arm 31 at which the pawl 45 engages the ratchet wheel. Rearward or clockwise movement of the arm 31 will result in the pawl 55 riding backward over the teeth of the ratchet 44. The ratchet wheel is prevented from moving backward or clockwise by a counterweighted pivoted detent 46 carried oy casing structure ll enclosing the speed reducing mechanism 25. g

The amount of motion imparted to the shaft 26 may be varied by varying the point at which the pawl engages the ratchet wheel on the forward movement of the arm 31. To this end, an adjustable arcuate member 48 is provided which is carried by the outer end of an arm 49 loosely mounted on the shaft 26. The arcuate member 48 prevents the pawl from engaging the teeth of the ratchet wheel when the member 48 is positioned within the arc of movement of the pawl, the pawl riding upon and sliding across the face of the member 43. The position of the member 58 may be varied by an arm 50 fixed to the arm 49 and pivotally connected to the lower end of an operating rod 5| having a handle 52 at its upper end (see Fig. l). The operating rod 5| may be held in any one of a number of desired positions by the engagement of a projection 53 thereon in any one of a plurality of slots or notches 54 in a member 55 fixed to the hopper 22.

As stated, the fuel is fed longitudinally of the duct 2! and upwardly into the combustion chamber H and onto the grate I! which extends laterally from the opening 20 therein. Air for combustion flows through the grate from a plenum chamber or wind box 56 beneath the grate, as will presently appear, and the fuel is burned on the grate H. The forward and rearward movement of the grate serves both to agitate the fuel .bed supported thereby and also to move the bed rearwardly of the furnace. The solid products of combustion or ash gravitates through the fuel bed toward the grate and is moved rearwardly thereby and is ejected from the furnace through an opening 57 defined by a rearward extension of the guide plate l8 and the underside of the rear wall |3. p

The method of feeding and burning the fuel just explained is known as underfeeding due to the fact the incoming green fuel is moved upwardly through the fuel bed. This type of feeding is admirably suited for burning high volatile coals, as is well known. However, anthracite, prepared coke, and other low-volatile'fuels may also be burned satisfactorily in this manner. The underfeeding of fuel onto a domestic stoker grate is of course well known, but due to the arrangement of the fuel feeding duct with respect to the walls of the combustion chamber, and to the construction of this duct and the construction and operation of the grate, my improved stoker is capable of burning without care by an attendant any type of solid fuel available, and particularly the highly caking or coking coals, which have not heretofore been burned satisfactorily without careful attendance and manual removal of clinker and ash from the fuel bed.

One of the principal novel features of my improved stoker is the means for breaking up or crushing any caked mass which might exist at the fuel inlet opening to the combustion chamber. As stated above, the grate I1 is provided with an opening or channel 20, the defining walls of which are arranged in the form of a U, and through which fuel is fed upwardly from the upper end of a stationary duct 2!. The front wall l2 extends across the open side of the channel 20 and the closed side or base is defined by a surface 58 which extends upwardly and rearwardly and at the same angle of inclination as the duct 2|. It will thus be seen that the channel 20 is in effect an extension or continuation of the duct 2!, and the two form in effect a single continuous conduit through which fuel is fed from the hopper 22 onto the upper surface of the grate H. The channel 28 forms an upper movable part of this conduit, and the duct 2| a lower stationary part. From an examination of Fig. 3, it will be observed that the upper end of the stationary duct 2| is provided by an opening or channel 59 through the guide plate I8. When the operation of the furnace is to be resumed after a shut down period, there usually exists within the opening or channel 20, due to the agglomerating properties of the fuel, a caked mass which must be broken up to permit the proper feed of fuel to the grate, and to effect the breaking up of this caked or agglomerated mass, I utilize the foreward and rearward movement of the grate, which movement crushes or breaks up the caked mass between the surface 58 and the front wall l2. In fact, the part of the structure which provides the surface 58 can be likened unto a wedge which moves transversely of the caked or agglomerated mass within the opening or channel 29 and towards and away from thewall l2, and thereby acts to crush or break up the said mass so as to permit the flow of fuel from the hopper 22, through the duct 2l,' through the opening or channel 20, and onto the grate structure to thus promote combustion.

The action just described is,,as stated, useful particularly when a caking coal is being burned and in starting up after a shut-down period. When the furnace is shut down, for example, by a thermostat in the house operating to open the switch of the motor, the fuelin the combustion chamber burns out and the inactive coal in and adjacent to the mouth of the fuel feeding conduit becomes caked. When the furnace is again started up the coaction between the moving inclined face.

58 and the caked coal column and the front wall l2, serve to quickly break up the caked coal and in almost immediately obtaining active combustion adjacent to the mouth of the conduit. The intensely active fire then in the region of the mouth through which green coal enters the furnace greatly facilitates ignition of the incoming coal and results in quickly bringing the furnace and fuel bed to a condition of maximum rate of heat output.

Referring to the detail construction and operation of the fuel supporting structure 16 it will be observed from an examination of Figs. to 12 inclusive that the horizontal guide plate l8 comprises a main plate-like portion 89 which extends for the length and width of the combustion chamber and includes a rearward extension 6| over which the ash moves. The plate I 8 also comprises wall structure defining the upwardly inclined opening 59 for the fuel, which was previously referred to and forms the upper part of the fuel feeding duct 21. A securing flange 62 is formed at the lower end of the opening 59 for the purpose of securing the flanged end 63 of the upper part of fuel feeding duct 2i. The guide plate I8 is provided with space'ddepending lugs 64 providing aligned journal bearing supports 65 for a grate operating shaft 66 (see also Figs. 2 and 3). The main plate-like portion 88 is provided with a U-shaped opening 61 through which air for combustion flows from the wind box 56 to the grate.

The grate l'l comprises a grate frame 68 and a plurality of grate bars 69, 19 and H. The grate frame 68 is shown in detail in Figs, 8 and as consisting of wall structure defining an opening 12 and a U-shaped opening 13, the opening 12 being a part of the opening 20 previously referred to and including the wedge shaped closed side 58, and the opening 13 surrounding the opening 12 and providing for the passage of the combustion supporting air to the grates. Spaced lugs and I8 depend from the frame 88 at each side of the opening 12 and are provided with aligned openings which receive a rod 11. Spaced links 18 and 19 are connected to the rod ii at the outside of the lugs 15 and i6 and operatively connect the rod TI and lugs 15 and 16 to the outer ends of arms 88 and 8| respectively, the latter being fixed at their other ends to the grate operating shaft The shaft 86 extends outside of the furnace structureand has fixed thereto an operating arm 82 having a series of openings 83 formed therein (see Fig. 1). The shaft 88 and arm 82 areoscillated by a link 84 pivotally connected at one end to the arm 82 by a pin 85 fitting a selected one of the openings 83 and pivotally connected at the other end to a crank 86 fixed to the extreme outer end 81 of the shaft- 26, the latter being previously described as also operating the fuel feeding screw 23. Thus, the grate frame with the grate bars thereon is reciprocated forwardly and rearwardly on the guide plate 18, and the amplitude of the reciprocations may be varied by changing the connection of the link 84 with the arm 82 to another of the remaining openings 83 in the arm 82.

As stated, the air-emitting grate surface is formed by the gratebars 69, "I8 and H supported by and fitting within the frame 68. The grate bars in assembled relation are shown in Figs. 5 and 9 and detail side elevations of grate bars 10 and 69 are shown in Figs. 11 and 12', respectively. Grate bars 69 are shorter and extend between the inclined portion 58 of the frame and the rear side thereof. Right angle notches 90 at the front of the grate bars 69 and u-shaped notches 9| at the rear serve to position the grate bars in the frame. The front upper face of each of the grate bars 69 is inclined, as indicated at 92, and forms a continuation of the face 58 of the frame. The grate bars 69 are provided with'air passages 93 for conducting the combustion supporting air to the fuel bed. Air may alsopass through the joints between grates 69, and such is true of all of the grate bars.

Grate bars 19 which flank the opening 28 are to position them within the frame 68 and are also provided with air passages 91 in the side thereof adjacent'the opening 20 for the purpose of directing the air into the fuel column within the opening 20. The passages 91 at their inner end communicate with spaces defined by the downwardly extending web portions of adjacent grate bars I0 and I I, and these spaces communicate in turn with the wind box 56.

Grate bars II are disposed in the frame 68 at the outside of the grate bars I0. The grates II are provided with notches (not shown) for positioning them within the frame 68 in the same manner as disclosed in connection with grate bars (-29 and 10. Each of the grate bars II is provided with air passages 98 in the sides of the upper portion thereof which communicate with the spaces defined by the downwardly extending web portions of adjacent grate bars and thereby serve as a means for conducting the air into the fuel bed. I

All of the grate bars are provided with aligned openings 99 which also align with openings I00 provided in the sides of the frame 88. A rod IOI extends through the aligned openings 99 and I00 and serves to lock the grate bars in position in the frame 68.

In addition to providing an underfeeding action, the direction of movement of the fuel entering the combustion chamber performs another and important function which is one of the principal features of the present invention. When a furnace of the small type shown is operating with normal fuel bed conditions, as distinguished from starting up after a shut-down period in the manner previously explained, the ignition and coking of the fuel for the most part takes place at points spaced from the mouth of the duct 2|,

and there is a pronounced tendency for the burning coked fuel to arch up and away from the grate, with the result that the-movement of the grate will have very little effect in breaking up the fuel bed. However, as will presently appear, due to my improved arrangement and manner of fuel feed and the relative size and position of the parts, the fuel bed on my grate is maintained in a broken-up or porous condition.

It will be observed from an examination of Figs. 3, 14 and 15 that fuel entering the combustion chamber moves in the general direction of the rear wall I3. When the furnace has operated for a short time and built up a'normal fuel bed, the entering fuel column maintains its columnlike formation throughout the length of the furnace, with the rear end of the column adjacent the rear wall. The force exerted by the screw 23 on the column of entering fuel will be transmitted thereby to the rear wall, and as a result the fuel in the column will be compressed to such an extent. that it will break up and spread laterally onto the grate and the motion of the latter will aid in keeping the fuel bed broken up. In other words, due to the direction of fuel feed and the position of the rear wall, the entering fuel column breaks itself up and thereby provides for the flow of air through the fuel bed and the burning out of the combustible therein. As a fuel column is broken up bycompression in the manner just explained, and the burning fuel spreads laterally onto the grate, the constantly incoming stream of fresh fuel maintains the columnlike formation across the furnace.

In Figs. 14 and 15 the fuel column is indicated at A. If the fuel is a caking typ the volatile constituents will be driven off as it moves toward the rear wall and the tarry substances in the fuel will exude and tend to bind the fuel together and thus prevent the necessary flow of air therethrough. The compression action just explained will cause the fuel bed to break up and the broken particles, which by this time will be practically solid carbon or coke, will spread laterally onto the sides of the grate. The coke particles are indicated at B. The solid non-combustibles gravitate to the lower portion of the fuel bed as ash and clinker which is fed out through the opening 51 by the reciprocating action of the grate. It is to be noted at this point that the movement of the grate also aids in breaking up the fuel bed. The ash is indicated at C and the clinker at D. In this connection it is to be noted that the ash piles up at the rear of the furnace and provides an inclined support for the rear end of the fuel column. This is important, as it maintains the direction of movement of the column A toward the rear wall so that the latter will be broken up by compression, as explained above.

Another and important advantage is attained from maintaining a bed of ash beneath the rear portions of the fuel bed when certain types of fuel are burned, for example, bituminous coals. This advantage is that the ash offers a substantial resistance to the flow of air through the rear portions of the bed and thereby assures adequate flow of air through the front portions of the fuel bed where the resistance to air flow is normally and relatively higher due to the. greater degree of coking action taking place at the front By varying the amountof accumulated ash, the resistance, to air flow may be changed to suit the of the grate, space is provided into which the broken up particles are permitted to spread laterally and burn.

The rate of ash discharge must be regulated so as to maintain the desired support for the fuel column, as just explained, and also so as to seal the outlet opening 51 against the harmful infiltration of air therethrough into the combustion chamber. According to my invention, I provide for a regulated rate of ash discharge and for the breaking up of any clinker formations therein. To this end, I provide a plate I05 which is positioned to partially close the opening 51 and is reciprocated in a vertical plane so as to shear or break up the clinker. The plate I05 is provided with teeth I06 on its forward surface which a feed the ash and clinker downwardly toward the opening and also crush and break them up. The lower edge of the plate will shear any clinker as the latter is moved out through the opening 5? by the reciprocating grate I'I.

The plate I05 is slidably mounted between the rear face fo the rear wall I3 and a pair of guide strips I01 secured to the side walls M and I5. The plate I05 is supported and reciprocated by pins I08 on the outer ends of arms I09 and engaging between spaced projections I I 0 fixed to the rear face'of the plate. The arms I09 are fixed to an operating shaft I I I which extends out of the furnace as shown in Fig. 1 and is provided with an arm II2 fixed thereto and having a retractible latch H3 at its outer end which maybe caused to engage any one of a series of notches II 4 formed on the outer arcuate surface of an arm H5. The arm H5 is loosely mounted on the shaft III and is provided with a depending porpin III] is placed. Thus, by changingthe pin to oscillatory motion of the arm 82 will be transmitted through the'link II1, arm II5, arm II2, shaft III, and arms I09 to the plate I05. The amplitude of reciprocation of the plate depends upon the particular opening within which the another opening the amplitude may be varied to suit diiferent operating conditions. The size of the ash discharge opening 51 may be varied by varying the position of the plate I05. This latter is effected through the retractible latch H3 and the series of notches II4.

The ash ejected through the opening 51 falls into a suitable receptacle I20, which may be re-.

placed by another receptacle when filled. This procedure will avoid the shoveling of ash in the basement, which causes objectionable dust.

Air for combustion is supplied to the wind box by a fan I2I driven directly by the motor 24 (see Figs. 1, 2, 3 and 13). The fan I2I comprises a rotor I22 connected to the shaft of the motor- 24, a casing I23 surrounding the rotor and having an inlet communicating with a duct I24 and an outlet communicating with the wind box 56.

In order to provide an adequate and even flow of air through the fuel bedat all times,.I provide an automatic control which operates to vary the air supply inaccordance with the resistance offered to the flow of air by the fuel bed. If the fuel bed is relatively porous or thin the pressure of air in the windbox is reduced by my control so that only the desired amount will flow through the fuel bed. If, on the other hand, thefuel bed is thick, or if it is caked or agglomerated to any extent the pressure of the air in the wind v box is increased by my control to an amount sufficient to force the desired amounts of air through the fuel bed.

I accomplish these very desirable results by pro viding a fan of high enough capacity to produce a pressure in the wind box sufficient to forceadequate amounts ofair through the fuel bed when the resistance offered thereby to the flow is the greatest that can be expected, and then by regulating the amount of air supplied to the inlet side of the fan in accordance with the rate of flow of the air to the fan.

The flow of air to the inlet of the fan is regulated by a damper I25'in the duct I24, and the damper is automatically controlled by the rate of air-flow through the duct I24. The damper I25 is connected by a linkage I26 with a flapper I21 pivotally mounted along one edge, as indiit about its pivotal support and open the damper I 25. One side of theflapper I21 is exposed to the pressure of the air in the duct and the other side is exposed to the atmosphere. The air inlet to the duct I24 is indicated I30 as being an orifice, the size of which may be varied by a slide damper I3I. As the entering air flows through the orifice, the pressure of the air within the duct is less than that of the atmosphere and the difference in pressure will depend on the size of the orifice and rate of air flow through the orifice/ With one side of the flapper exposed to the air pressure in the duct and the other side to .fuel bed to any desired amount.

the atmosphere, the flapper will move against its own weight to close the damper I25 until the force created by the differences in pressure and that resulting from the weight of the damper are balanced. If the rate of air flow varies due to changes in the resistance offered by the fuel bed to the flow of air therethrough, the difference in pressure between that of the duct and that of the atmosphere. will change and the flapper I21 will move to a new position of equilibrium and move the damper I 25 to admit more air or less air, as the case may be. Adjustments of the slide damper I3I to vary the orifice I30 will change the amount of air flowing through the The slide damper I3I may-be regulated by a control lever I32 operating through a link I33, lever I34 and link I35. I

The construction thus far described is highly compact and conveniently arranged and may be enclosed in a suitable and attractive casing. Due to the inclined coal feeding duct 2i and the height of the fuel supporting surface I 6, the coal feeding hopper 22 may be placed relatively low so as to require the of labor in filling, and an ash receptacle I may be provided which may be quickly and easily removed and another placed in its stead. I have found that in operation, noattention is required to the The furnace may be operated automatically by a room thermostat or by other suitable devices, and all that is required is to keep fuel in the hopper and replace the ash receptacle. The thermostat may be connected to the control switch of the motor 24 which operates both the fuel feeding screw and the fan. No need is had for poking the fire or manual removal of clinker, even though low grade or highly coking in a porous condition during normal operation- The latter is aided by the position and manner of ash discharge. for the purpose of providing the best operation for the type of fuel burned and for the desired heat output or capacity of the furnace.

- In Fig. 16, I have illustrated a possible modification of my invention. The fuel feeding duct 2Ia is illustrated, as being substantially vertical atits inlet end. The desirable feature of shearing or breaking up the entering fuel is attained by the grate I1a. having the opening 20a'defined by U-shaped walls and moving transversely of the mouth of the duct 2Ic to crush the fuel against the front wall.- The same type of ash discharge is provided as in the previously described modification.

In Fig. 1'7, I have illustrated a further modification of the fuelfeeding duct. The duct is indicated at 2|.b and the mouth thereof is' arranged more horizontally than the duct -2I in the first embodiment described andthus provides a more positive crushing action of the fuel feeding column against the rear wall I3b. However, the breaking up of the column at the mouth of the duct is not positive like that of the previously described design because the grate is not provided with an opening defined by U-shaped walls and the grate does not move transversely across the mouth of the fuel feed- The various adjustments are ing duct. However, in Fig. 1'7, a breaking up action will be hadat the mouth of the duct 2lb due to the upward wedging action of the inclined front face I40 of the moving grate.

While I have shown my invention in one preferred embodiment and have suggested .two

modifications, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

I claim:-

1. In combustion apparatus, the combination of means defining a combustion chamber including front and rear upwardly extending wall portions, means for feeding solid fuel into the combustion chamber at points adjacent the front wall portion and in a direction extending upwardly and toward the rear wallvportion so that the fuel in entering moves in a column extending across the combustion chamber from the front wall portion towards the rear wall portion whereby the column of fuel breaks up due to the crushing action against the rear wall portion, and a member movable transversely across the fuel column as it enters thecombustion chamber and toward and away from the front wall portion so as to crush 'therebetween anycaked mass which may exist in the space where the fuel column enters the combustion chamber.

2. In combustion apparatus, the combination of means defining a combustion chamber ineluding front and rear upwardly-extending ,wall

portions, means for feeding solid fuel into the combustion chamber including a duct having the end thereof adjacent the combustion chamber upwardly inclined toward the rear wall portion and entering the combustion chamber at points adjacent the front wall portion so that the fuel column is crushed against the rear wall portion and thereby broken up, and a wedge-shaped member movable transversely of the mouth of the duct and towards and away from the front wall portion so as to break up any caked mass which may exist at the mouth of the duct.

3. In combustion apparatus, the combination of means defining a combustion chamber and including upwardly extending front and rear wall portions; means providing a substantially flat fuel-supporting surface extending across the lower end of the combustion chamber; means for feeding fuel onto the fuel-supporting surface at points adjacent the front wall portion and insuch a manner that the fuel moves across the the level of the fuel supporting surface and opening in the direction of the rear wall, and

means outside of said chamber for positivelypushing solid fuel through saidconduit and onto said fuel supporting surface; means providing an ash discharge orifice beneaththe rear wall said. last-named portion; and means providing for the reciprocation of at least a portion of the fuel-support ing surface towards and away from the ash discharge orifice for feeding the ash through said 4. In a combustion apparatus, the combination of means defining a combustion chamber including an upwardly extending rear wall portion; means providing a substantially fiat fuel-supporting surface extending across the lower end of the combustion chamber and including an airemitting grate structure movable toward and away from-the rear wall portion; said grate structure having a channel extending therethrough at a point remote from the rear wall portion; said channel being of substantially less width than the grate structure, and being inclined upwardly and toward the rear wall portion; and means for forcing fuel through the channel and onto said grate structure so that the fuel moves in a column across the grate structure and strikes the rear wall portionand is broken up by compression against said rear wall portion and spread laterally onto said grate structure.

5. In combustion apparatus, the combination of means defining a combustion chamber including front and rear upwardly extending wall portions; a fuel-supporting grate structure extending across the lower part of said combustion chamber; means for positively forcing solid fuel into the combustion chamber at a point adjacent the front wall portion and in a direction extending toward the rear wall portion so that the fuel moves across the grate structure .in a column of substantially less width than the grate structure and strikes the rear wall portion, whereby the column is continually broken up by compression against said rear wall portion and the broken particles are spread laterally onto the grate structure; said grate structure including means for crushing a portion of the fuel column against the front wall portion where said column enters said combustion chamber so as to accelerate ignition and promote active combustion of the column upon resumption of fuel feed following a period of inactivity; and means for reciprocating said grate structure toward and from said front wall portion.

6. In combustion apparatus, the combination of front, rear and side wall parts defining a combustion chamber; a substantially flat grate extending across the lower part of said combustion chamber; a fuel-feeding conduit having an open outlet end communicating with the combustionchamber at a point adjacent the front wall part and between the side wall parts at the level of the grate and being of substantially less width than the distance between the side wall parts;

the open outlet end of said conduit being arranged to discharge solid fuel towards saidrear wall part; means for positively forcing solid fuel through said conduit and into said combustion chamber so that the fuel moves across said grate in a column of substantially less width than the grate andstrikes the rear wall part, whereby the column is continually broken up by compression againstthe rear wall part and the broken parti-' cles are spread laterally onto the grate; means providing for reciprocatory movement of the grate towards and away from the rear wall part eral direction as the direction of movement of the fuel column; and means adjacent the rear a so as to feed the resulting ash in the same gen- 2,148,834 wall for permitting the removal of ash from the combustion chamber.

7. In combustion apparatus, the combination of front, rear and side wall parts defining a combustion chamber; a substantially flat grate extending across the lower part of said combustion chamber; a fuel-feeding conduit having an open outlet end communicating with the combustion chamber at a point adjacent the front wall part and between the side wall parts at the level of the grate, and being of substantially less width than the distance between the side wall parts; the open outletend of said conduit being arranged to discharge solid fuel towards said rear wall parts; means for positively forcing solid fuel through said conduit and into said combustion chamber so that the fuel moves across said grate in a column of substantially less width than the grate and strikes the rear wall part, whereby the column is' continually broken up by compression against the rear wall part and the broken particles are spread laterally onto the grate; means providing for reciprocatory movement of the grate towards and away from the rear wall part so as to feed the resulting ash in the same general direction as the direction of movement of the fuel column; and means adjacent the'rear wall for permitting the removal of ash from the combustion chamber; said grate including means for crushing a portion of the fuel column against the front wall part where said column enters said combustion chamber so as to accelerate ignition and promote active combustion of the column upon resumption of fuel feed following a period of inactivity.

8. In combustion apparatus, the combination of front, rear, and side wall parts defining a combustion chamber; a substantially flat grate extending across the lower part of said combustion chamber; a fuel-feeding conduit having an open outlet end communicating with the combustion chamber at a point adjacent the front wall part and between the said wall parts at the level of the grate, and being of subtsantially les's width than the distance between the side wall parts; the open outlet end of said conduit being arranged to discharge solid fuel towards said rear wall part; means for positively forcing solid fuel through said conduit and into said combustion chamber so that the fuel moves across said grate in a column of substantially less width than the grate and strikes the rear wall part, whereby the column is continually broken up by compression against the rear wall part and the broken particles are spread laterally onto the grate; means providing for reciprocatory movement of the grate towards and away from the rear wall part so as to feed the resulting ash in the same general direction as the direction of movement of the fuel column; means adjacent the rear wall for permitting the removal of ash from the combustion chamber; and means for regulating the rate of ash discharge with respect to the rate of fuel feed so as to maintain a supporting bed of ash beneath that part of the column which is closer to the rear wall part and assure the engagement between the end of said column and said rear wall part.

9. In combustion apparatus, the combination of means defining a combustion chamber and including front, side and rear walls; a fuel feeding conduit extending into said combustion chamber at a point adjacent the central portion only of the front wall and positioned to discharge fuel in a single general direction upwardly and toward'the rear wall; a fuel supporting grate extending laterally and .rearwardly from the upper open end of said conduit and toward said side walls and rear wall respectively, said grate having an opening through its front central portion coextensive with and registering with the upper open end of said conduit, the walls defining the sides of the opening in the grate being spaced from the side walls of the combustion chamber to form at each side of said opening a lateral fuel supporting surface of substantial width; and

means for positively forcing solid fuel longitudinally of the conduit through said opening in said grate structure, into said combustion chamber and upwardly. and rearwardly toward said rear wall, so that the fuel is forced into the combustion chamber in the form of a narrow column, the inner end of which is forced into contact with the rear wall to thereby break up the column and spread portions thereof into the said lateral fuel supporting surface at each side of said column. 10.. Apparatus according to claim 9 wherein means are provided for discharging the resulting ash from the combustion chamber and where in such means are adjustable to vary the rate of ash discharge so as to maintain within the combustion chamber adjacent therear wall thereof, a supporting bed of ash beneath the inner end of the fuel column.

11. In combustion apparatus, the combination of means defining a combustionchamber' and including front, side and'rear walls; a grate arranged across the lower part of said combustion chamber and having a fuel feeding opening extending therethrough at a point adjacent the front wall and spaced from the side and rear walls with the defining walls of said opening arranged in the form of a U and with the grate so positioned that the front wall of the combustion chamber extends across the open side of said opening, the walls of said grate which define the sides of said opening being spaced from the side walls of the combustion chamber to form at each side of said opening a lateral fuel supporting surface of substantial width; a stationary duct having an open outlet end arranged below said grate and registering with said opening; means for positively forcing solid fuel through said duct and onto said grate through said opening and in a direction extending toward the rear wall of said combustion chamber, so that fuel is forced into the combustion chamber in the form of a narrow column, the inner end of which is forced into contact with the rear wall tothereby break up the column to spread portions thereof onto the said lateral fuel supporting surfaces at each side of said column; and means providing for reciprocatory movement toward and away from said front wall of at least that partof said grate which defines said opening so that the part of the grate which is opposite said front wall will crush against said front wall any coked mass of fuel which may exist in the space where the fuel prising the steps of producing a burning fuel bed; 7|

positively and continuously forcing a narrow stream of coking coal through the fuel bed intermediate the sides of said fuelbed, whereby the outer surface of said stream is coked by the heat of said fuel bed; arresting the movement of the inner end of said' stream; utilizing the force exerted on the narrow stream by the pressure of the incoming fuel to set up within said'stream internal pressure sufficient to break off and spread laterally the coked outer surface of said stream as the same is formed and to thus expose the surface of the inner raw fuel of said stream to "coking action; and continuing the burning of the coked particles Continuously broken off from the surface ,of said stream as such particles spread laterally into said fuel bed. 7

14. The method of burning a coking coal comprising the steps of producing a burning fuel bed; positively and continuously forcing a narrow stream of coking coal through the fuel bed intermediate the sides of said fuel bed, whereby the outer surface of said stream is coked by the heat of said fuel bed; arresting the movement of the inner end of said stream; maintaining a supporting bed of ash beneath the inner end of said stream; utilizing the force exerted on the narrow stream by the pressure of the incoming fuel to set up within said stream internal pressure sufficient to break off and spread laterally the coked outer surface of said stream as the same is formed and to thus expose the surface of the inner raw fuel of said stream to coking action; and continuing the burning of the coked particles continuously broken off from the surface of said stream as such particles spread laterally into said fuel bed.

DONALD J. MOSSHART. 

